diff --git a/src/uas/UAS.cc b/src/uas/UAS.cc
index 073c940eeb739298ebe158371f26061d3f1f93ed..39882258ea5bacfba6d44d239abd31752fb35c1e 100644
--- a/src/uas/UAS.cc
+++ b/src/uas/UAS.cc
@@ -1259,8 +1259,10 @@ void UAS::enableExtra3Transmission(int rate)
  * @param id Name of the parameter
  * @param value Parameter value
  */
-void UAS::setParameter(int component, QString id, float value)
-{    
+void UAS::setParameter(const int component, const QString& id, const float value)
+{
+    if (!id.isNull())
+    {
     mavlink_message_t msg;
     mavlink_param_set_t p;
     p.param_value = value;
@@ -1288,6 +1290,7 @@ void UAS::setParameter(int component, QString id, float value)
     }    
     mavlink_msg_param_set_encode(mavlink->getSystemId(), mavlink->getComponentId(), &msg, &p);
     sendMessage(msg);
+    }
 }
 
 /**
diff --git a/src/uas/UAS.h b/src/uas/UAS.h
index 410b15e4a23362a93946744c8972ce72b16979dd..bb0333184ae68410628a12f1e62d25d5e3f5862c 100644
--- a/src/uas/UAS.h
+++ b/src/uas/UAS.h
@@ -239,7 +239,7 @@ public slots:
     void requestParameters();
 
     /** @brief Set a system parameter */
-    void setParameter(int component, QString id, float value);
+    void setParameter(const int component, const QString& id, const float value);
 
     /** @brief Write parameters to permanent storage */
     void writeParametersToStorage();
diff --git a/src/uas/UASInterface.h b/src/uas/UASInterface.h
index 8bbc716b981360663a4592aecf532689384f3a62..0b00419907cbe0d5b7f3af47a2f9250683bbb325 100644
--- a/src/uas/UASInterface.h
+++ b/src/uas/UASInterface.h
@@ -214,7 +214,7 @@ public slots:
      * @warning The length of the ID string is limited by the MAVLink format! Take care to not exceed it
      * @param value Value of the parameter, IEEE 754 single precision floating point
      */
-    virtual void setParameter(int component, QString id, float value) = 0;
+    virtual void setParameter(const int component, const QString& id, const float value) = 0;
 
     /**
      * @brief Add a link to the list of current links
@@ -327,8 +327,14 @@ signals:
       * @param value the value that changed
       * @param msec the timestamp of the message, in milliseconds
       */
+
+    // FIXME Exchange the lines below against the commented ones
     void valueChanged(int uasId, QString name, double value, quint64 msec);
     void valueChanged(UASInterface* uas, QString name, double value, quint64 msec);
+
+//    void valueChanged(const int uasId, const QString& name, const double value, const quint64 msec);
+//    //void valueChanged(UASInterface* uas, QString name, double value, quint64 msec);
+
     void voltageChanged(int uasId, double voltage);
     void waypointUpdated(int uasId, int id, double x, double y, double z, double yaw, bool autocontinue, bool active);
     void waypointSelected(int uasId, int id);
diff --git a/src/ui/HUD.cc b/src/ui/HUD.cc
index 0832671744731c374bdd5f588fa47834a9c5a907..2d57262366913602c610f7d03373abf9178f9230 100644
--- a/src/ui/HUD.cc
+++ b/src/ui/HUD.cc
@@ -285,7 +285,7 @@ void HUD::updateAttitudeThrustSetPoint(UASInterface*, double rollDesired, double
 
 void HUD::updateAttitude(UASInterface* uas, double roll, double pitch, double yaw, quint64 timestamp)
 {
-    qDebug() << __FILE__ << __LINE__ << "ROLL" << yaw;
+    //qDebug() << __FILE__ << __LINE__ << "YAW" << yaw;
     updateValue(uas, "roll", roll, timestamp);
     updateValue(uas, "pitch", pitch, timestamp);
     updateValue(uas, "yaw", yaw, timestamp);
diff --git a/src/ui/linechart/LinechartPlot.cc b/src/ui/linechart/LinechartPlot.cc
index 49194b5fab210ea896fd8501cc37a83e90925250..606c3bddf61be9313659c276b2e481b0c196b077 100644
--- a/src/ui/linechart/LinechartPlot.cc
+++ b/src/ui/linechart/LinechartPlot.cc
@@ -254,7 +254,8 @@ void LinechartPlot::appendData(QString dataname, quint64 ms, double value)
     if(ms < minTime) minTime = ms;
     if(ms > maxTime) maxTime = ms;
     storageInterval = maxTime - minTime;
-    lastTime = time;
+
+    if(time > lastTime) lastTime = time;
 
     //
     if (value < minValue) minValue = value;
@@ -276,6 +277,8 @@ void LinechartPlot::appendData(QString dataname, quint64 ms, double value)
 void LinechartPlot::enforceGroundTime(bool enforce)
 {
     m_groundTime = enforce;
+
+    lastTime = QGC::groundTimeUsecs()/1000;
 }
 
 /**